Field of the Invention
The present invention relates to control systems for fuel injection pumps, and in particular to systems to limit transient smoke during sudden changes in the throttle position of a turbocharged engine.
Description of the Related Art
Emissions regulations for diesel engines include limits on peak, acceleration, and lug exhaust smoke levels as measured by the US Federal Smoke Cycle. High brake mean effective pressure (BMEP) turbocharged engines cannot meet the peak and acceleration smoke limits without the use of devices that delay high fuel deliveries until sufficient turbocharger boost pressure is available for adequate combustion.
This delay can currently be accomplished in two different ways. First is to use an electronic delay. This requires an electronically metered fuel system which may or may not be present on the vehicle. Second is to use an aneroid control which detects the turbocharger pressure directly and uses it to control the fuel injection volume. Such an aneroid requires an intake manifold pressure tap, piping, pressure-to-motion transducer and complicated internal pump linkages.